So basically in process of rebuilding this atv for fun more then anything, its an older Gio Beast 200-250cc(unsure really)

So got it all running well with new carb and wiring harness electrical, and out for a spin.....chain kept popping off.
had a closer look and the swing arm is noticeably loose and allows play in the rear end enough to slacking the chain and pop it off.

Took it all apart and noticed it has good nylon or Poly bushings on frame side but nothing but bare metal in the actual swingarm. I measured the holes and they are 12.5mm big on the swing arm and the bolt/axle is 12mm

Is there a option for replaceable bushings in the swing arm?

I am looking for any options you all might have encountered, including boring the swing arm holes larger and installing some larger bushings etc.

Anything, want to get this thing going.